Oxygen-glucose deprivation activates 5-lipoxygenase mediated by oxidative stress through the p38 mitogen-activated protein kinase pathway in PC12 cells.
5-Lipoxygenase (5-LOX) is a key enzyme catalyzing arachidonic acid to form leukotrienes. We have reported that ischemic-like injury activates 5-LOX in PC12 cells; however, the mechanisms are unknown. To determine whether ischemic-like injury activates 5-LOX mediated by oxidative stress through the p38 MAPK pathway, we transfected GFP-5-LOX into PC12 cells and induced ischemic-like injury by oxygen-glucose deprivation (OGD). We found that the transfected GFP-5-LOX was localized primarily in the nuclei and translocated to the nuclear envelope after OGD/recovery reaching a maximum 2 hr after a 2-hr exposure to OGD. The nonselective 5-LOX inhibitor caffeic acid, 5-LOX-activating protein inhibitor MK886, and selective 5-LOX inhibitor zileuton attenuated the cell injury and reduced the production of 5-LOX products, cysteinyl leukotrienes, after OGD/recovery. However, only caffeic acid inhibited OGD/recovery-induced 5-LOX translocation. OGD/recovery also increased reactive oxygen species (ROS), which was inhibited by caffeic acid only. Hydrogen peroxide, an exogenous ROS, evoked similar cell injury and 5-LOX translocation, and the inhibitors had effects on the changes after H(2)O(2) similar to those after OGD/recovery. Both OGD/recovery and H(2)O(2) increased the phosphorylated p38 MAPK level, which was inhibited by caffeic acid and the ROS scavenger edaravone, but not by MK886 or zileuton. Moreover, SB203580 (a p38 MAPK inhibitor) and edaravone inhibited the cell injury and 5-LOX translocation induced by OGD/recovery and H(2)O(2). Thus, we conclude that OGD/recovery-induced ischemic-like injury induces 5-LOX activation, which is mediated by oxidative stress through activating the p38 MAPK pathway.
Li
Cheng-Tan
CT
Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China.
Zhang
Wei-Ping
WP
Lu
Yun-Bi
YB
Fang
San-Hua
SH
Yuan
Yu-Mei
YM
Qi
Ling-Ling
LL
Zhang
Li-Hui
LH
Huang
Xiao-Jia
XJ
Zhang
Lei
L
Chen
Zhong
Z
Wei
Er-Qing
EQ
D058927:5-Lipoxygenase-Activating Proteins; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D000983:Antipyrine / Q000031:analogs & derivatives / Q000494:pharmacology; D001094:Arachidonate 5-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D002109:Caffeic Acids / Q000494:pharmacology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors; D015687:Cell Hypoxia; D000077553:Edaravone; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006918:Hydroxyurea / Q000031:analogs & derivatives / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D015289:Leukotrienes / Q000378:metabolism; D016859:Lipoxygenase Inhibitors; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000037:antagonists & inhibitors; D018384:Oxidative Stress / Q000502:physiology*; D016716:PC12 Cells; D010766:Phosphorylation / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000494:pharmacology; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002722:Chlorobenzenes
D058927:5-Lipoxygenase-Activating Proteins; D000975:Antioxidants; D000983:Antipyrine; D001094:Arachidonate 5-Lipoxygenase; D002109:Caffeic Acids; D002352:Carrier Proteins; D000077553:Edaravone; D004791:Enzyme Inhibitors; D005947:Glucose; D006861:Hydrogen Peroxide; D006918:Hydroxyurea; D007093:Imidazoles; D007211:Indoles; D015289:Leukotrienes; D016859:Lipoxygenase Inhibitors; D008565:Membrane Proteins; D011725:Pyridines; D017382:Reactive Oxygen Species; D048051:p38 Mitogen-Activated Protein Kinases; C060893:MK-886; D002722:Chlorobenzenes; C093642:SB 203580; C040048:caffeic acid; C063449:zileuton